The present invention relates to a method for producing an olefin polymer. More particularly, the present invention relates to a method for producing an olefin polymer using a transition metal compound represented by a metallocene complex, which does not require use of an aromatic hydrocarbon as a solvent.
In the present invention, the olefin polymer includes a homopolymer of an olefin and a copolymer of a plurality of olefins.
It has been reported that a catalyst for polymerization, comprising a transition metal compound, particularly a diimine complex or a transition metal complex containing one or two groups having a cyclopentadiene type anionic skeleton, e.g. a so-called non-metallocene complex or metallocene complex, respectively, and aluminoxane exhibits a high activity. Particularly, when the metallocene complex is used, an olefin polymer having narrow molecular weight distribution and composition distribution, that is, the resulting olefin polymer exhibits considerably useful feature from industrial point of view. Therefore, a lot of reports have recently been made (e.g. Japanese Patent Publication (Kokai) No. Sho 58-19309). It has also been reported that high activity is exhibited in the olefin polymerization in case of a system using no aluminoxane, that is, in a method using a specific boron compound (e.g. Japanese Patent Publication (Kohyo) No. Hei 1-502036, Japanese Patent Publication (Kokai) Nos. Hei 6-157651, Hei3-163088 and Hei3-188092).
Since already known transition metal compounds such as ethylenebis(indenyl)zirconium dichloride, isopropylidene(cyclopentadienyl)(fluorenyl)zirconium dichloride, dimethylsilyl(tert-butylamide)(tetramethylcyclopentadienyl)titanium dichloride, etc. are soluble in an aromatic hydrocarbon solvent such as toluene, etc., but hardly dissolve in an aliphatic hydrocarbon solvent. Therefore, the transition metal compound was normally handled in the form of a solution of the aromatic hydrocarbon solvent.
Furthermore, the above boron compound is a particulate solid and has a problem that it dissolves in the aromatic hydrocarbon solvent such as toluene, etc. to some extent but its solubility in the other solvent, particularly aliphatic hydrocarbon solvent, is very low. In general, in the polymerization of an olefin using a conventional transition metal compound, it is obliged to use the aromatic hydrocarbon solvent such as toluene, etc. Such a solvent is liable to remain in a polymer as the product to give off an odor, resulting in a large problem.
An object of the present invention is to provide a method of producing an olefin polymer using a transition metal compound, which does not require use of an aromatic hydrocarbon solvent which is liable to remain in a polymer as the product to give off an odor.
That is, according to the present invention, there is provided a catalyst for olefin polymerization obtained using (A) and (C) described below or a method for producing an olefin polymer, which comprises homopolymerizing or copolymerizing olefins in the presence of a catalyst for olefin polymerization obtainable by using the following (A) (B) and (C) as catalyst components:
(A): a transition metal complex dissolved, suspended or slurried in an aliphatic hydrocarbon compound;
(B): a compound dissolved, suspended or slurried in an aliphatic hydrocarbon compound, which is selected from the following (B1) to (B3):
(B1) an organoaluminum compound represented by the general formula E1aAlZ3-a;
(B2) a cyclic aluminoxane having a structure represented by the general formula {xe2x80x94Al(E2)xe2x80x94Oxe2x80x94}b; and
(B3) a linear aluminoxane having a structure represented by the general formula E3{xe2x80x94Al(E3)xe2x80x94Oxe2x80x94}cAlE32 (wherein E1 to E3 respectively represents a hydrocarbon group having 1 to 8 carbon atoms, and all of E1, E2 and E3 may be the same or different; Z represents a hydrogen atom or a halogen atom, and all of Z may be the same or different; a represents a numeral satisfying 0 less than axe2x89xa63; b represents an integer of not less than 2; and c represents an integer of not less than 1); and
(C): at least one boron compound suspended or slurried in an aliphatic hydrocarbon compound, which is selected from the following (C1) to (C3):
(C1) a boron compound represented by the general formula BQ1Q2Q3;
(C2) a boron compound represented by the general formula G+(BQ1Q2Q3Q4)xe2x88x92; and
(C3) a boron compound represented by the general formula (L-H)+(BQ1Q2Q3Q4)xe2x88x92
(in each of the above general formulae, B is a boron atom in the trivalent valence state, Q1-Q4 are a halogen atom, a hydrocarbon group, a halogenated hydrocarbon group, a substituted silyl group, an alkoxy group or a di-substituted amino group, which may be the same or different, respectively. G+ is an inorganic or organic cation, L is a neutral Lewis base, and (L-H)+ is a Brxc3x8nsted acid.)
The present invention will be described in detail hereinafter.
All of the components (A) and component (C) or the additional component (B), which constitute the catalyst for olefin polymerization of the present invention, do not require an aromatic hydrocarbon compound as a solvent. As the solvent for dissolving, suspending or slurrying these catalyst components, an aliphatic hydrocarbon solvent is used.
(A) Transition Metal Component
The component (A) of the catalyst for polymerizing an olefin used in the present invention is a dissolved, suspended or slurried transition metal component.
The transition metal compound is preferably a compound of Group III-XII or lanthanide series of the Periodic Table of the Elements (1993, IUPAC), and various transition metal compounds having an olefin polymerization activity (e.g. metallocene complex, non-metallocene complex, etc.) can be employed. A transition metal compound of Group IV or lanthanide series is more preferred, and a transition metal compound having at least one cyclopentadiene type anionic skeleton, i.e. metallocene transition metal compound is most preferred.
The metallocene transition metal compound is a compound represented by the following general formula (3): General formula (3) MLaR3p-a 
(wherein M represents a transition metal compound of Group IV or lanthanide series of the Periodic Table of the Elements (1993, IUPAC); L represents a group having a cyclopentadiene type anionic skeleton or a group having a hetero atom, at least one of which is a group having a cyclopentadiene type anionic skeleton, and a plurality of L may be the same or different and may be crosslinked each other; R3 represents a halogen atom or a hydrocarbon group having 1 to 20 carbon atoms; a represents a numeral satisfying 0 less than axe2x89xa6p; and p represents a valence of a transition metal atom M).
In the general formula (3) representing the metallocene transition metal compound, M is a transition metal compound of Group IV or lanthanide series of the Periodic Table of the Elements (1993, IUPAC). Specific examples of the transition metal atom of Group IV include a titanium atom, a zirconium atom, a hafnium atom, etc., and specific examples of the transition metal atom of lanthanide series include a samarium atom. Among them, titanium atom, zirconium atom or hafnium atom is preferred.
In the general formula (3) representing the metallocene transition metal compound, L is a group having a cyclopentadiene type anionic skeleton or a group having a hetero atom, at least one of which is a group having a cyclopentadiene type anionic skeleton, and a plurality of L may be the same or different and may be crosslinked each other.
Examples of the group having a cyclopentadiene type anionic skeleton include xcex75-cyclopentadienyl group, xcex75-substituted cyclopentadienyl group or a polycyclic group having a cyclopentadiene type anionic skeleton. Examples of the substituent of the xcex75-substituted cyclopentadienyl group include hydrocarbon group having 1 to 20 carbon atoms, halogenated hydrocarbon group having 1 to 20 carbon atoms or silyl group having 1 to 20 carbon atoms. Examples of the polycyclic group having a cyclopentadiene type anionic skeleton include xcex75-indenyl group, xcex75-fluorenyl group, etc.
Examples of the hetero atom in the group having a hetero atom include nitrogen atom, phosphorous atom, oxygen atom, sulfur atom, etc. Examples of the group having such a hetero atom include hydrocarbylamino group, hydrocarbylphosphino group, hydrocarbyloxy group, hydrocarbylthio group, etc., preferably alkoxy group, aryloxy group, alkylthio group, arylthio group, dialkylamino group, diarylamino group, dialkylphosphino group and diarylphosphino group.
Specific examples of the xcex75-substituted cyclopenatdienyl group include xcex75-methylcyclopentadienyl group, xcex75-ethylcyclopentadienyl group, xcex75-n-propylcyclopentadienyl group, xcex75-isopropylcyclopentadienyl group, xcex75-n-butylcyclopentadienyl group, xcex75-isobutylcyclopentadienyl group, xcex75-sec-butylcyclopentadienyl group, xcex75-tert-butylcyclopentadienyl group, xcex75-1,2-dimethylcyclopentadienyl group, xcex75-1,3-dimethylcyclopentadienyl group, xcex75-1,2,3-trimethylcyclopentadienyl group, xcex75-1,2,4-trimethylcyclopentadienyl group, xcex75-tetramethylcyclopentadienyl group, xcex75-pentamethylcyclopentadienyl group, xcex75-trimethylsilylcyclopentadienyl group, etc.
Specific examples of the polycyclic group having a cyclopentadiene type anionic skeleton include xcex75-indenyl group, xcex75-2-methylindenyl group, xcex75-4-methylindenyl group, xcex75-4,5,6,7-tetrahydroindenyl group, xcex75-fluorenyl group, etc.
Specific examples of the group having a hetero atom include methoxy group, ethoxy group, propoxy group, butoxy group, phenoxy group, methylthio group, dimethylamino group, diethylamino group, dipropylamino group, dibutylamino group, diphenylamino group, pyrrolyl group, dimethylphosphino group, etc.
The groups having a cyclopentadiene type anionic skeleton, or the group having a cyclopentadiene type anionic skeleton and the group having a hetero atom may be crosslinked each other. In that case, an alkylene group (e.g. ethylene group, propylene group, etc.), a substituted alkylene group (e.g. dimethylmethylene group, diphenylmethylene group, etc.) or a substituted silylene group (e.g. silylene group, dimethylsilylene group, diphenylsilylene group, tetramethyldisilylene group, etc.) may exist between the groups.
R3 in the general formula (3) representing the metallocene transition metal compound is a halogen atom or a hydrocarbon group having 1 to 20 carbon atoms. a is a numeral satisfying 0 less than axe2x89xa6p, and p is a valence of a transition metal atom M. Specific examples of R3 include a fluorine atom, a chlorine atom, a bromine atom, iodine atom as the halogen atom and methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, phenyl group, benzyl group and the like as the hydrocarbon group having 1 to 20 carbon atoms. R3 is preferably a chlorine atom, methyl group or benzyl group.
Among metallocene transition metal compounds, specific examples of the compound wherein the transition metal atom M is a zirconium atom include bis(cyclopentadienyl)zirconium dichloride, bis(methylcyclopentadienyl)zirconium dichloride, bis(pentamethylcyclopentadienyl)zirconium dichloride, bis(indenyl)zirconium dichloride, bis(4,5,6,7-tetrahydroindenyl)zirconium dichloride, bis (fluorenyl)zirconium dichloride, ethylenebis(indenyl)zirconium dichloride, ethylenebis(4,5,6,7-tetrahydroindenyl)zirconium dichloride, isopropylidene(cyclopentadienyl)(fluorenyl)zirconium dichloride, dimethylsilylenebis(cyclopentadienyl)zirconium dichloride, dimethylsilylenebis(4,5,6,7-tetrahydroindenyl)zirconium dichloride, dimethylsilylene(cyclopentadienyl)(fluorenyl)zirconium dichloride, diphenylsilylenebis(indenyl)zirconium dichloride, (cyclopentadienyl)(dimethylamide)zirconium dichloride, (cyclopentadienyl)(phenoxy)zirconium dichloride, dimethylsilyl(tert-butylamide)(tetramethylcyclopentadienyl)zirconium dichloride, bis(cyclopentadienyl)zirconium dimethyl, bis(methylcyclopentadienyl)zirconium dimethyl, bis(pentamethylcyclopentadienyl)zirconium dimethyl, bis(indenyl)zirconium dimethyl, bis(4,5,6,7-tetrahydroindenyl)zirconium dimethyl, bis(fluorenyl)zirconium dimethyl, ethylenebis(indenyl)zirconium dimethyl, dimethylsilyl(tert-butylamide)(tetramethylcyclopentadienyl)zirconium dimethyl, etc.
There can also be exemplified compounds wherein zirconium of the above zirconium compounds is replaced by titanium or hafnium.
These metallocene transition metal compounds may be used alone or in combination of two or more.
The component (A) of the catalyst for olefin polymerization used in the present invention is a transition metal compound dissolved, suspended or slurried in the aliphatic hydrocarbon compound, and a transition metal compound dissolved in the aliphatic hydrocarbon compound is preferably used.
Examples of the transition metal compound soluble in such an aliphatic hydrocarbon compound, include isopropylidene(cyclopentadienyl)(3-tert-butyl-5-methyl-2-phenoxy)titanium dichloride, dimethylsilyl(tetramethylcyclopentadienyl)(3-tert-butyl-5-methyl-2-phenoxy)titanium dichloride, etc.
(B) organometallic Component
The component (B) used in the present invention is a compound dissolved, suspended or slurried in an aliphatic hydrocarbon compound, which is selected from (B1) an organoaluminum compound represented by the general formula E1aAlZ3-a, (B2) a cyclic aluminoxane having a structure represented by the general formula {xe2x80x94Al(E2)xe2x80x94Oxe2x80x94}b and (B3) a linear aluminoxane having a structure represented by the general formula E3{xe2x80x94Al(E3)xe2x80x94Oxe2x80x94}cAlE32 (wherein E1 to E3 respectively represents a hydrocarbon group having 1 to 8 carbon atoms, all of E1, all of E2 and all of E3 may be the same or different; Z represents a hydrogen atom or a halogen atom, and all of Z may be the same or different; a represents a numeral satisfying 0 less than axe2x89xa63; b represents an integer of not less than 2; and c represents an integer of not less than 1).
Specific examples of the organoaluminum compound (B1) represented by the general formula E1aAlZ3-a include trialkylaluminum such as trimethylaluminum, triethylaluminum, tripropylaluminum, triisobutylaluminum, trihexylaluminum, etc.; dialkylaluminum chloride such as dimethylaluminum chloride, diethylaluminum chloride, dipropylaluminum chloride, diisobutylaluminum chloride, dihexylaluminum chloride, etc.; alkylaluminum dichloride such as methylaluminum dichloride, ethylaluminum dichloride, propylaluminum dichloride, isobutylaluminum dichloride, hexylaluminum dichloride, etc.; and dialkylaluminum hydride such as dimethylaluminum hydride, diethylaluminum hydride, dipropylaluminum hydride, diisobutylaluminum hydride, dihexylaluminum hydride, etc.
Among them, trialkylaluminum is preferred and triethylaluminum or triisobutylaluminum is more preferred.
Specific examples of E2 and E3 in (B2) a cyclic aluminoxane having a structure represented by the general formula {xe2x80x94Al(E2)xe2x80x94Oxe2x80x94}b and (B3) a linear aluminoxane having a structure represented by the general formula E3xe2x80x94{Al(E3)xe2x80x94Oxe2x80x94}cAlE32 include alkyl group such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, n-pentyl group, neopentyl group, etc. b is an integer of not less than 2, c is an integer of not less than 1. Each of E2 and E3 is preferably methyl group or isobutyl group. b is from 2 to 40 and c is from 1 to 40.
The above aluminoxane is prepared by various methods. The method is not specifically limited, and the aluminoxane may be prepared according to a known method. For example, the aluminoxane is prepared by contacting a solution, which is obtained by dissolving a trialkylaluminum (e.g. trimethylaluminum, etc.) in a suitable organic solvent (e.g. benzene, aliphatic hydrocarbon, etc.) with water. Also, there can be illustrated a method for preparing the aluminoxane by contacting a trialkylaluminum (e.g. trimethylaluminum, etc.) with a metal salt containing crystal water (e.g. copper sulfate hydrate, etc.).
(C) Third Component
As the component (C) in the present invention, there can be used one or more boron compounds selected from the following (C1) to (C3):
(C1) a boron compound represented by the general formula BQ1Q2Q3;
(C2) a boron compound represented by the general formula G+(BQ1Q2Q3Q4)xe2x88x92; and
(C3) a boron compound represented by the general formula (L-H)+(BQ1Q2Q3Q4)xe2x88x92.
In the boron compound (C1) represented by the general formula BQ1Q2Q3, B is a boron atom in the trivalent valence state; Q1 to Q3 may be the same or different and represent a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms, a halogenated hydrocarbon group having 1 to 20 carbon atoms, a substituted silyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms or an amino group having 2 to 20 carbon atoms. Q1 to Q3 are preferably a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms or a halogenated hydrocarbon group having 1 to 20 carbon atoms.
Specific examples of the compound (C1) include tris(pentafluorophenyl)borane, tris(2,3,5,6-tetrafluorophenyl)borane, tris(2,3,4,5-tetrafluorophenyl)borane, tris(3,4,5-trifluorophenyl)borane, tris(2,3,4-trifluorophenyl)borane, phenylbis(pentafluorophenyl)borane, etc., most preferably tris(pentafluorophenyl)borane.
In the boron compound (C2) represented by the general formula G+(BQ1Q2Q3Q4)xe2x88x92, G+ represents an inorganic or organic cation; B is a boron atom in the trivalent valence state; and Q1 to Q4 are as defined in Q1 to Q3 in the above (1).
Specific examples of G+ as an inorganic cation in the compound represented by the general formula G+(BQ1Q2Q3Q4)xe2x88x92 include ferrocenium cation, alkyl-substituted ferrocenium cation, silver cation, etc. Examples of the G+ as an organic cation include triphenylmethyl cation. G+ is preferably a carbenium cation. Examples of (BQ1Q2Q3Q4)xe2x88x92 include tetrakis(pentafluorophenyl)borate, tetrakis(2,3,5,6-tetrafluorophenyl)borate, tetrakis(2,3,4,5-tetrafluorophenyl)borate, tetrakis(3,4,5-trifluorophenyl)borate, tetrakis(2,3,4-trifluorophenyl)borate, phenyltris(pentafluorophenyl)borate, tetrakis(3,5-bistrifluoromethylphenyl)borate, etc.
Specific combination of these include ferroceniumtetrakis(pentafluorophenyl)borate, 1,1xe2x80x2-dimethylferroceniumtetrakis(pentafluorophenyl)borate, silvertetrakis(pentafluorophenyl)borate, triphenylmethyltetrakis(pentafluorophenyl)borate, triphenylmethyltetrakis(3,5-bistrifluoromethylphenyl)borate, etc., most preferably triphenylmethyltetrakis(pentafluorophenyl)borate.
In the boron compound (C3) represented by the formula (L-H)+(BQ1Q2Q3Q4)xe2x88x92, L represents a neutral Lewis base; (L-H)+ represents a Brxc3x8nsted acid; B represents a boron atom in the trivalent valence state; and Q1 to Q4 are as defined in Q1 to Q3 in the above (C1).
Specific examples of (L-H)+ as a Brxc3x8nsted acid in the compound represented by the general formula (L-H)+(BQ1Q2Q3Q4)xe2x88x92 include trialkyl-substituted ammonium, N,N-dialkylanilinium, dialkylammonium, triarylphosphonium, etc., and examples of (BQ1Q2Q3Q4)xe2x88x92 include those as defined above.
Specific combination of them includes triethylammoniumtetrakis(pentafluorophenyl)borate, tripropylammoniumtetrakis(pentafluorophenyl)borate, tri(n-butyl)ammoniumtetrakis(pentafluorophenyl)borate, tri(n-butyl)ammoniumtetrakis(3,5-bistrifluoromethylphenyl)borate, N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate, N,N-diethylanilinium tetrakis(pentafluorophenyl)borate, N,N-2,4,6-pentamethylaniliniumtetrakis(pentafluorophenyl)borate, N,N-dimethylaniliniumtetrakis(3,5-bistrifluoromethylphenyl)borate, diisopropylammonium tetrakis (pentafluorophenyl)borate, dicyclohexylammonium tetrakis (pentafluorophenyl)borate, triphenylphosphonium tetrakis(pentafluorophenyl)borate, tri(methylphenyl)phosphoniumtetrakis(pentafluorophenyl) borate, tris(dimethylphenyl)phosphoniumtetrakis (pentafluorophenyl)borate, etc., and tri(n-butyl) ammoniumtetrakis(pentafluorophenyl)borate or N,N-dimethylanilinumtetrakis(pentafluorophenyl)borate is most preferable.
As the component (C), (C2) or (C3) is preferred and triphenylmethyltetrakis(pentafluorophenyl)borate or N,N-dimethylaniliniumtetrakis(pentafluorophenyl)borate is particularly preferred. N,N-dimethylaniliniumtetrakis(pentafluorophenyl)borate is most preferred.
In the present invention, as the catalyst for olefin polymerization, a catalyst for olefin polymerization, obtainable by using the above (A) and (C) as the catalyst component, or a catalyst for olefin polymerization, obtainable by using the above (A), (B) and (C) as the catalyst component is used. Preferably, a catalyst for olefin prepared by continuously feeding a part or all of the respective catalyst components in an apparatus for preparing a catalyst, or a catalyst for olefin prepared by continuously feeding the respective catalyst components in an apparatus for olefin polymerization is used. In case of feeding in the apparatus for preparing a catalyst or the apparatus for olefin polymerization, the respective catalyst components can be used by charging in an arbitrary order, but an arbitrary combination thereof may be used after previous contact.
In the present invention, the respective catalyst components are sometimes used in the state suspended or slurried in the aliphatic hydrocarbon compound. Herein, in the present invention, the state suspended or slurried in the solvent means the state in which a solid is not completely dissolved in the solvent but solid particles are dispersed in the solvent. In the present invention, the suspended state and slurried state are not particularly distinguished.
In the present invention, when the above respective catalyst components are fed in the state suspended or slurried in a solvent, the sedimentation velocity of each of the catalyst components in the suspended or slurried state is preferably lower than the flow velocity in a pipeline so that each of the catalyst components are not deposited in the pipeline.
In the present invention, the solvent used for dissolving, suspending or slurrying in the solvent is not specifically limited as far as it is an aliphatic hydrocarbon compound which causes no problem in use of the respective catalyst components. Specific examples thereof include butane, hexane, heptane, octane, cyclohexane, dodecane, liquid paraffins, etc.
In the present invention, it is preferable to use a solvent having a high viscosity so that the sedimentation velocity of the respective catalyst components in the suspended or slurried state is lower than the flow velocity in the pipeline. The viscosity of the solvent is preferably not less than 0.8 cp (centipoise), more preferably 1.4 to 1200 cp, most preferably 1.6 to 50 cp.
Specific examples of solvents having a high viscosity include dodecane, various liquid paraffins, mixed solvents of these with other solvents. As the liquid paraffins, for example, commercially available liquid paraffins having various viscosities within about 2 to about 2000 cp can be used. Besides, the viscosity referred to herein means the viscosity at 20xc2x0 C.
Such a high-viscosity solvent is preferably used as the solvent of the above component (C), furthermore, preferably used as the solvent of the above components (C) and (A).
In the present invention, when a pipeline is used in case of feeding the respective catalyst components to the apparatus for preparing a catalyst or apparatus for olefin polymerization, a diameter of the pipeline is not specifically limited, but is from 0.5 to 100 mm, preferably from 1 to 50 mm, more preferably from 1.5 to 30 mm.
The concentration of the respective catalyst components is appropriately selected according to the conditions such as performances of the apparatus for feeding the respective catalyst components to a polymerization reactor, and the respective catalyst components are preferably used so that the concentration of (A) is normally from 0.01 to 500 xcexcmol/g, preferably from 0.05 to 100 xcexcmol/g, more preferably from 0.05 to 50 xcexcmol/g; the concentration of (B) is normally from 0.01 to 10000 xcexcmol/g, preferably from 0.1 to 5000 xcexcmol/g, more preferably from 0.1 to 2000 xcexcmol/g, in terms of Al atom; and the concentration of (C) is normally from 0.01 to 500 xcexcmol/g, preferably from 0.05 to 200 xcexcmol/g, more preferably from 0.05 to 100 xcexcmol/g.
The above component (C) and majorities of the component (A) are soluble in an aromatic hydrocarbon solvent such as toluene, etc. to some extent, but hardly dissolve in an aliphatic hydrocarbon solvent. Although the amount of the above component (C) contained in the solution is small, particularly, the component (C) can be fed in a large amount and smaller volume by using a method of feeding the respective catalyst components in the suspended or slurried state in the solvent, favorably.
The above component (C) can be fed in the amount of 0.0001 to 800 mmol/liter, preferably 0.001 to 500 mmol/liter, in terms of the number of moles of the boron compound based on the volume of the solvent.
The respective catalyst components in the catalyst for olefin polymerization used in the present invention are preferably used so that a molar ratio of the component (B)/the component (A) is within the range from 0.1 to 10000, preferably from 5 to 2000, and a molar ratio of the component (C)/the component (A) is within the range from 0.01 to 100, preferably from 0.5 to 10.
As the olefin, which can be applied to the polymerization in the present invention, all of olefins having 2 to 20 carbon atoms can be used and two or more olefins can also be used, simultaneously. Specific examples of the olefin include straight-chain xcex1-olefins such as ethylene, propylene, butene-1, pentene-1, hexene-1, heptene-1, octene-1, nonene-1, decene-1, etc.; branched xcex1-olefins such as 3-methylbutene-1, 3-methylpentene-1, 4-methylpentene-1, 5-methyl-2-pentene-1, etc.; and vinylcyclohexane, but should not be limited to the above compounds in the present invention. Examples of the combination of olefins in the copolymerization include ethylene and propylene, ethylene and butene-1, ethylene and hexene-1, ethylene and octene-1, propylene and butene-1, etc., but should not be limited to these combinations in the present invention.
The present invention can be effectively applied to the preparation of the copolymer of ethylene and xcex1-olefin (e.g. propylene, butene-1, 4-methylpentene-1, hexene-1, octene-1), particularly.
Also, the polymerization method should not be specifically limited. For example, there can be performed solvent polymerization or slurry polymerization using an aliphatic hydrocarbon such as butane, pentane, hexane, heptane, octane, etc. as the solvent, high-pressure ionic polymerization in the absence of a solvent under high temperature and high pressure, gas phase polymerization in a gaseous monomer, etc. The polymerization can be performed in a continuous manner or a batch-wise manner.
More preferably, the preferable polymerization method in the present invention includes a high-temperature solution method of polymerizing an olefin under the conditions of 120 to 250xc2x0 C. and 5 to 50 kg/cm2 where the polymer is molten, using a solvent such as cyclohexane, etc. and a high-pressure ionic polymerization method of polymerizing an olefin in a super critical fluid state under high temperature and high pressure in the absence of a solvent in the state where the produced polymer is molten.
More preferably, the polymerization is performed at under a pressure of at least 300 kg/cm2, preferably 350 to 3500 kg/cm2 at a temperature of at least 130xc2x0 C., preferably 135 to 350xc2x0 C. In this case, as a polymerization form, both of a batch-wise manner and a continuous manner are possible, but it is preferable to perform in the continuous manner. As a reactor, a stirring type vessel reactor or a tubular reactor can be used. The polymerization can be performed in a single reaction zone. Alternatively, the polymerization can also be performed by partitioning one reactor into a plurality of reaction zones or connecting a plurality of reactors in series or parallel. In case of using a plurality of reactors, both of a combination of a vessel reactor and another vessel reactor and a combination of a vessel reactor and a tubular reactor are used. In a method of polymerizing using a plurality of reaction zones or a plurality of reactors, polymers having different characteristics can also be produced by changing the temperature, pressure and gas composition of each reaction zone.
The respective catalyst components are normally fed to the reactor with a high-pressure pump. In such a polymerization under high pressure, for introducing the catalyst into the high-pressure portion with a pump, the catalyst is preferably liquid-form, is homogeneously dissolved in a solvent, or is particle small in a particle diameter and good in dispersity when it is solid insoluble in a solvent. In that case, the maximum particle diameter is preferably 50 xcexcm or less, more preferably 30 xcexcm or less, particularly 10 xcexcm or less, most preferably 5 xcexcm or less.
In order to control the particle diameter of the boron compound (C), there can be applied a pulverization method and a method of adding dropwise a solution obtained by dissolving it in toluene to an aliphatic hydrocarbon solvent such as heptane, etc. for precipitating.
A catalyst solution is normally handled under an inert gas atmosphere such as nitrogen, argon, etc. so that it is not brought into contact with water and air.
The polymerization time is appropriately determined according to the kind of the desired polymer and reactor, and the conditions are not specifically limited. In the present invention, a chain transfer agent such as hydrogen, etc. can also be added to control the molecular weight of the copolymer.